Mechanical maintenance is taken as meaning
the replacement and repair of non-electrical parts of equipment,
as well as the cleaning and replacement of lamps. Thus,
we are considering the means of making safe electrical equipment
which is to be worked on by non-electrical people.

Such switches must be:

1.
- easily and clearly identified by those who need
to use them

2. - arranged
so that there can be no doubt when they are on or off

3. - close
to the circuits or equipment they switch

4. - able
to switch off full load current for the circuit concerned

5. - arranged
so that it is impossible for them to be reclosed unintentionally.

Where mechanical maintenance requires access
to the interior of equipment where live parts could be exposed,
special means of isolation are essential. Lamps should be
switched off before replacement.